Half of his eight to a



2 Sheets-Sheet 1.' W. N; De- GROAT. Rotary-Engine.

No. 224,999. atente d Mar. 2,

N-PETERs PHOTO-LITHDGRAPHER, -WA$H|NGTON. D. C.

2 Sheets-Sheet 2.

W. N. D e GROAT. Rotary-Engine.

No. 224.999. Patented Mar.'2, 1880.

'N-FETERS, PHOTQLITNOGIRANER, WASHINGTON. D. G.

, UNITED STATES PATENT OFFICE.

WILLIAM N. DE GROAT, OF KNOXVILLE, TENNESSEE, ASSIGNOR OF ONE- HALF OFHIS RIGHT TO A. L. MAXWELL, OF SAME PLACE.

ROTARY ENGINE.

SPECIFICATION forming part of Letters Patent No. 224,999, dated March 2,1880.

i Application filed January 10, 1879.

To all whom it may concern:

Be it known that I, WILLIAM NELsON DE GROAT, of Knoxville, in the countyof Knox and State of Tennessee, have invented certain new and usefulImprovements in Rotary Engines, of which the following is aspecification.

My engine is constructed with a disk mounted on a shaft and havingapiston-head, which works in a stationary annular cylinder so as toimpart rotation to the disk and thereby to the shaft.

The steam and exhaust ports enter the disk at or near its center andpass to its periphery in opposite directions, the steam-port c'om'mur 5nicating with the cylinder through one face of the piston-head, and theexhaust-port at a diametrically opposite point. The necessary abutmentsare formed by radial] y-slidin g heads operated by a cam-wheel on themain shaft. The exhaust-port and other parts are so arranged that eachsliding head is relieved of pressure before it has to be moved, and itis restored to its place under a pressure which is balanced, with theexception of the small area of the stem by which it is worked.

For a reversing-engine I employ a steamport on each face of thepiston-head and a plugin the disk having connection-ports,which, byturning the plug in either direction, are caused to place either of thesaid ports in the head in communication with the central steamport ofthe disk, and the other with the exhaust-port.

I prefer to use three radially-sliding abutments toa disk having onepiston-head. The invention may be used to good advantage with twopiston-heads on the rotary disk and a corresponding number of mainexhaust-ports intermediately arranged, and with four radially-slidingabutment-heads in the annular cylinder.

In order that my invention may be fully un-.

A represents a suitable base or bed, on which the standards orpillow-blocks B B and the annular cyl nder (J are fastened. The mainshaft S has its bearings on the pillow-blocks B B, and has keyed on itsforward end a disk, 1), on which are one or more piston-heads, E,fitting within the annular cylinder 0. F F are packing-rings set upagainst the faces of the disk D in customary manner, in order to confinethe steam within the annular cylinder.

Gr represents the stationary steam-supply pipe, communicating with thecenter of the disk D, and H the exhaust-pipe, which communicatesconstantly with an annular exhaustport, H, in the disk surrounding thecentral steam-port, G, which communicates with the steam-pipe G. Thesteam-pipe G is confined, and the joint between it and the rotary disk Dpacked by means of a gland, I. From the central steam-portin the disk aport, g, extends radially to a plug, J, by which said radial steam-portis made to communicate with the port 9 or 9 on either side of thepistonhead E, according to the direction in which the engine is to run.The other port, 9 or g, as the case may be, is, by the same adjustmentof the plug, placed in communication with the exhaust-port h? or it,connecting with the annular exhaust-port H. The ports in the plug toadapt it to thus control the steam and the 8 movement of the engine areshown in Fig. 1, g being a Y or V shaped port, to connect the centralsteam-port, g, with either of the ports g 9 and h k curved exhaust-portswhich connect the other port, or g, with the exhaust- 5 port k or h, asbefore stated.

The main exhaust-port of the disk is shown at H This port is alwaysopen, and is located diametrically opposite the piston-head E, where buta single piston is used. If two 9 pistons are used, the respectiveexhaust-ports are located a short distance in advance of them, asillustrated in Fig. 3; but this arrangement is not suitable for areversing-engine. V

In non-reversing engines, with either one or more pistons, thereversing-plug J and its accessories may be entirely omitted, the stopping and starting being effectually controlled by the throttle.

K K K are the radially-sliding abutments,

which are operated by rods L, passing through stuffing-boxes M, andconnected, by arms N i and rods 0, to levers P, fulcrumed at p, and

having on their shorter arms spherical frictionrollers 19, which travelin the cam-groove q of a wheel, Q, keyed on the main shaft S.

The form of the cam-groove q is such that each radially-sliding head Kis withdrawn a short time before the-piston E reaches that point in thecylinder, and is closed again directly behind the piston.

It will further appear from the positions of the parts shown in Fig.1that each sliding head or abutment is relieved of steam-pressure beforethe next preceding abutment is retracted for the passage of the piston.

In the position shown in Fig. 1 the main exhaust-port H has just clearedthe space from shown in Fig. 2, whereby it delivers it through thefloor, is convenient.

The exhaust-pipe H may be turned in any radial direction.

I prefer to connect the stationary steam and exhaust port with the webnear its central part, as described; but this is not essential to theinvention.

T shows a driving-pulley on the shaft S.

Having thus described my invention, what I claim as new, and. desire tosecure by Letters Patent, is

l. The combination of the cylinder 0, rotatin g disk D, having one ormore piston-heads, E, the steam-pipe G, in line with the solid shaft S,the central and radial steam-ports G g within the rotating disk D, theradially-sliding abutments K K K the cam-wheel Q, and the levers P P P,substantially as and for the purposes described.

2. The combination, with the cylinder 0, disk D, and piston-head E, ofthe steam-ports G g g g exhaust-ports H H h 71. and the plug or valve J,provided with channels 9 and W, and turning on an axis parallel withthat of the disk, substantially as and for the purposes set forth.

3. The combination of the cylinder 0, solid shaft S, rotary disk 1),piston-head E, abutments K K K, annular exhaust-port H, and the externalradial exhaust-pipe H, com municatin g directly with said annularexhaust-port H, substantially as and for the purposes set forth.

WM. N. DE GROAT.

Witnesses OOTAVIUS KNIGHT, WALTER ALLEN.

